Rivaroxaban and apixaban are direct oral anticoagulants (DOACs) used for the prevention and treatment of various thromboembolic disorders. Predictable pharmacokinetic (PK) and pharmacodynamic (PD) properties, coupled with a few drug-drug and food-drug interactions, distinguishes DOACs from traditionally used anticoagulant - warfarin, allowing fixed dosing without routine coagulation monitoring. Patients with human immunodeficiency virus (HIV) are living as long as their HIV negative counterparts due to safe and efficacious antiretroviral therapy (ART). Persons with HIV are at higher risk for thromboembolic events and DOACs are a feasible option for anticoagulation in this population. However, there is a lack of drug interaction and safety data currently on the co-administration cobicistat (COBI)-boosted antiretroviral (ARV) regimens with rivaroxaban and apixaban. Rivaroxaban and apixaban are both metabolized by cytochrome P450 isozyme (CYP) 3A4 and their absorption is modulated by permeability-glycoprotein (P-gp), both of which are inhibited by the PK booster COBI. It is therefore possible that plasma concentrations of rivaroxaban and apixaban may be significantly increased when co-administered together with COBI. This is of clinical concern as increased anticoagulant exposure may result in bleeding without the security of routine clinical monitoring. The purpose of this study is to determine the effects of steady state concentrations of COBI and DRV/COBI on the PK and PD of single oral doses of rivaroxaban and apixaban.